1. Field of the Invention
The present invention relates to a record player with a radially or tangentially scanning tone arm for the scanning of sound record disks, where the vertical recording track angle .alpha. is to be maintained within predetermined limits, but where the absolute value of the recording track angle is unknown and where the tone arm is provided with a scanning system including a converter, which comprises elastically supported and therefore movable scanning elements for the generation of useful signals.
2. Brief Description of the Background of the Invention Including Prior Art
It is known that cutting systems and scanning systems employed in the recording and the reproduction of sound records have to maintain in each case certain angle tolerances with respect to the vertical track angle in order that a flawless and faultless music transmission is assured. It has been internationally agreed that the track angle for the sound recording cutter .alpha. is equal to 20 degrees minus 0 degrees plus 5 degrees and that the track angle for the scanner .beta. is equal to 20 degrees plus/minus 5 degrees.
In fact, in many cases the scanning track angle region is surpassed substantially in part as can be proved. The larger the difference between the track angles of the recording and of the scanning, the larger also are the nonlinear distortions during reproduction. While the scanning track angle .beta. can be determined by anyone at any time with a correspondingly calibrated and standardized test record disk, it is, on the other hand, completely impossible to state anything about which recording angle .alpha. is present on any arbitrary music sound recording. For this reason, it is not possible to provide in each individual case coincidence and matching of these two track angles.
The dependence of the nonlinear distortions, called FIM=Frequency Intermodulation, on the recording track angle for a scanning system with the vertical scanning angle .beta. is illustrated in FIG. 1. Under these circumstances, an amount of frequency intermodulation of about 2.5% would occur for the scanning of sound records which were recorded with an angle .alpha.=20 degrees. The frequency intermodulation situation is illustrated in FIG. 2 at a predetermined recording track angle .alpha.=20 degrees or, respectively, .alpha.=25 degrees. The tolerance region of the scanning track angle .beta. can be seen in the hatched region. For example, it can be concluded from this representation that in the case of actually available values, the frequency intermodulation increases to 10.3% if a scanning track angle .beta.=15 degrees is present and where a sound record is scanned with the recording track angle .alpha.=25 degrees. However, this is an unacceptable deterioration of the reproduction quality. It is further known from the state of the art that scanning systems or tone arms can be produced which are adjustable in vertical direction in order to allow the adjustment by the operator for a correction of the vertical scanning track angle .beta. as is taught in the German Patent DE-PF 220 2880.
However, it is disadvantageous in this context that the track angle .alpha. recorded in each case of the sound record remains unknown and thus the optimal arrangement of the scanner can at best be found by chance.